(CNN) -- The homicide rate in Mexico's most violent city -- Ciudad Juarez -- is down, according to Mexican President Felipe Calderon, but some residents of the city are not convinced.

"We are facing an entirely political statement, which is not based on reality. A statistic must be considered as a long process and not in a comparison of one month to another," Ciudad Juarez criminologist Oscar Maynes said.

Over the weekend, Calderon said homicides had fallen by 60% in Juarez since last October, comparing statistics from that month with April's numbers.

Speaking during an event that commemorated the city's 100th anniversary and its participation in the Mexican Revolution, Calderon said Juarez was "going through a time of darkness" and defended his crime-fighting strategy.

"There are probably variations and jumps [in the murder rate] because the evil of criminals are still there, but we must persevere in our efforts," he said.

But several days after Calderon's departure, some residents remained skeptical of his assessment.

"The president just came here and (violence) went down, but to say 60 or 70% is a lie -- he just left and the violence continues," Juarez resident Gaspar Rocha told CNN. "You have seen what has happened in the past and it will continue and continue and (Calderon) will leave. They're just words...it's a lie."

University professor Hugo Almada cautioned that the government should take a more measured approach.

"It seemed to me that the tone of the speech was very triumphant, and it should have been more moderate, because we have already had other moments in which it seems there a slight decrease in the situation, and later it picks up again," he said.

October 2010 saw a record of 359 homicides in the city, according to figures kept by the Chihuahua state attorney general's office.

The deadliest month was followed by 198 homicides in November and 213 in December. The pace of homicides continued into the New Year, with 215 killed in January and 231 in February. In March and April 2011 there were 176 and 271 homicides, respectively.

In his speech, Calderon used figures from the country's public safety secretary, which said there had been 166 homicides in April and 417 in October 2010.

The state attorney general's office said there has been a marked decrease in homicides in May, with 118 victims so far.

Maynes said the recent decline is due to multiple factors, but not to police or intelligence strategies of government officials.

"Violence is down at the border, but they have killed many people. People with resources have gone, or are paying an extortion fee, but I do not see any strategy that is working," Maynes said.

To accurately measure a trend, it's necessary to compare rates over a one-year period, not month to month, Maynes said.

"We have to recognize that the economy has not improved, the shops are closed -- that is the most valid demonstration. The effect is not just felt in terms of border killings, but also kidnapping, extortion and assaults," he added.

During Calderon's visit, state officials said they were beginning a new effort to help re-brand the city's violent image: changing its name.

Government officials approved a name change to "Heroic Ciudad Juarez" to emphasize the city's participation in the Mexican Revolution, but only as a symbolical slogan and not for official purposes, said Enrique Serrano Escobar, coordinator with the office of Chihuahua state representatives.

Homicides in Juarez, which borders El Paso, Texas, are often attributed to two violent drug cartels battling for turf in the city.

Ciudad Juarez is the city with the highest number of homicides in Mexico, with a record 8,000 victims since 2008, according to the Chihuahua state attorney general's office.

But this week, the city saw a brief respite.

For 28 hours, between 7 p.m. Monday and 11 p.m. Tuesday, there were no reports of homicides.